US20140118016A1 - Probes With Spring Mechanisms For Impeding Unwanted Movement In Guide Holes - Google Patents

Abstract

Elongated flexible probes can be disposed in holes of upper and lower guide plates of a probe card assembly. Each probe can include one or more spring mechanisms that exert normal forces against sidewalls of holes in one of the guide plates. The normal forces can result in frictional forces against the sidewalls that are substantially parallel to the sidewalls. The frictional forces can reduce or impede movement parallel to the sidewalls of the probes in the holes.

Description

BACKGROUND
• Some types of probe card assemblies comprise elongated probes each disposed within holes of spaced apart guide plates. As terminals of an electronic device to be tested are pressed against contact ends of the probes, the probes can slide in the holes in the guide plates and/or bend, which can ensure that opposite ends of the probes are compressed between the terminals of the electronic device being tested and terminals of the probe card assembly. Because the probes can move within the holes in the guide plates, however, the probes can move out of position prior to using the probe card assembly to test an electronic device. Additionally, the movement of probes in the holes can make assembly operations and repair operations of the probe card assembly more difficult. Embodiments of the present invention can inhibit such unwanted movement of the probes and thus avoid problems arising from such unwanted movement.
SUMMARY
• In some embodiments, a probe card assembly can include electrically conductive terminals disposed on a substrate, and a probe assembly coupled to the substrate. The probe assembly can include a guide plate and electrically conductive probes. Each probe can include a base end, a contact end, and an elongated flexible body between the base end and the contact end. A portion of the body can be disposed inside one of the guide holes and can include a first spring mechanism configured to exert a normal force against sidewalls of the guide hole. The normal force can be sufficiently large to reduce movement of the probe in the guide hole.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1A is a bottom, perspective view of an example of a probe card assembly according to some embodiments of the invention.
• FIG. 1B is a side, cross-sectional view of the probe card assembly ofFIG. 1A.
• FIG. 1C is a detailed view of an upper body portion of a probe disposed in a guide hole and comprising a spring mechanism for impeding inadvertent movement of the probe in the guide hole according to some embodiments of the invention.
• FIG. 2A is a side, cross-sectional partial view of a probe in which the spring mechanism comprises a cantilevered beam according to some embodiments of the invention.
• FIG. 2B shows the cantilevered beam ofFIG. 2A in a fully compressed state.
• FIG. 2C shows the probe ofFIG. 2A inserted into a guide hole of a guide plate.
• FIG. 3 is a side, cross-sectional partial view of a probe in which the spring mechanism comprises multiple beams each supported at both ends according to some embodiments of the invention.
• FIG. 4 is a side, cross-sectional partial view of a probe in which the spring mechanism comprises a beam supported at both ends according to some embodiments of the invention.
• FIG. 5A is a side, cross-sectional view of the probe card assembly ofFIGS. 1A-1C but with a probe having a compressible stop structure according to some embodiments of the invention.
• FIG. 5B is a detailed view of the compressible stop ofFIG. 5A according to some embodiments of the invention.
• FIG. 5C is a detailed view of the compressible stop ofFIG. 5B in a compressed state according to some embodiments of the invention.
• FIG. 6A is a side, cross-sectional partial view of a probe in which the compressible stop structure comprises a cantilevered beam according to some embodiments of the invention.
• FIG. 6B is a side, cross-sectional partial view of the probe ofFIG. 6A in which the compressible stop structure comprising a cantilevered beam is compressed according to some embodiments of the invention.
• FIG. 7A is a side, cross-sectional partial view of a probe in which the compressible stop structure comprises a hollow bulb structure according to some embodiments of the invention.
• FIG. 7B is a side, cross-sectional partial view of the probe ofFIG. 6A in which the compressible stop structure comprising a hollow bulb structure is compressed according to some embodiments of the invention.
• FIG. 8 shows an example of a test system in which the probe card assembly ofFIGS. 1A-1C can be used according to some embodiments of the invention.
• FIG. 9 shows an example of a probe in which a lower portion of the probe body that is inside a guide hole in a lower guide plate is offset from an upper portion of the probe body that is inside a guide hole in an upper guide plate according to some embodiments of the invention.
• FIG. 10 shows an example in which a guide hole in a lower guide plate is offset from a guide hole in an upper guide plate according to some embodiments of the invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
• This specification describes exemplary embodiments and applications of the invention. The invention, however, is not limited to these exemplary embodiments and applications or to the manner in which the exemplary embodiments and applications operate or are described herein. Moreover, the Figures may show simplified or partial views, and the dimensions of elements in the Figures may be exaggerated or otherwise not in proportion for clarity. In addition, as the terms “on,” “attached to,” or “coupled to” are used herein, one object (e.g., a material, a layer, a substrate, etc.) can be “on,” “attached to,” or “coupled to” another object regardless of whether the one object is directly on, attached, or coupled to the other object or there are one or more intervening objects between the one object and the other object. Also, directions (e.g., above, below, top, bottom, side, up, down, under, over, upper, lower, horizontal, vertical, “x,” “y,” “z,” etc.), if provided, are relative and provided solely by way of example and for ease of illustration and discussion and not by way of limitation. In addition, where reference is made to a list of elements (e.g., elements a, b, c), such reference is intended to include any one of the listed elements by itself, any combination of less than all of the listed elements, and/or a combination of all of the listed elements.
• As used herein, “substantially” means sufficient to work for the intended purpose. “Substantially parallel” means within plus or minus five degrees of parallel. “Substantially normal” means within plus or minus five degrees of normal. “Substantially orthogonal” means within plus or minus five degrees of orthogonal. “Substantially perpendicular” means within plus or minus five degrees of perpendicular.
• The term “ones” means more than one. “Elongated” means having a length dimension that is greater than any other dimension.
• Directions are, at least at times, illustrated in the Figures and referred to herein with regard to orthogonal axes x, y, and z. A z direction refers to a direction that is parallel to the z axis. As illustrated in the Figures, the z axis and thus a z direction can be vertical, and the x, y plane can be horizontal. Alternatively, the x, y, and z axes can be oriented other than with the z axis vertical.
• In some embodiments of the invention, elongated flexible probes disposed in corresponding holes of upper and lower guide plates of a probe card assembly can include one or more spring mechanisms that exert normal forces against sidewalls of the holes in one of the guide plates. The normal forces result in frictional forces against the sidewalls that are substantially parallel to the sidewalls, which can reduce or impede movement of the probes in the holes.
• FIGS. 1A-1C illustrate an example of aprobe card assembly100 comprisingprobes140 each having aspring mechanism162 for exerting normal (i.e., substantially in a plane that is parallel to the x, y plane) forces against thesidewalls160 of anupper guide hole126 in anupper guide plate124, which thereby provide a frictional force that is substantially parallel to thesidewalls160 according to some embodiments of the invention. The frictional force can reduce or impede unwanted movement of theprobe140 in theupper guide hole126 that is parallel to thesidewalls160.
• As shown, theprobe card assembly100 can comprise anelectrical interface104, awiring substrate102, and aprobe assembly120. As will be discussed below with regard toFIG. 8, theinterface104 can provide electrical connections to and from a tester for controlling testing of anelectronic device180. Theelectronic device180 can be, for example, one or more semiconductor dies (singulated or unsingulated from the semiconductor wafer from which the dies were fabricated) and/or other types of electronic devices. Theinterface104 can comprise any electrical connector that provides multiple electrical connections. Theinterface104 can be, for example, one or more zero-insertion-force electrical connectors, pogo pin pads, or the like.
• As shown, theinterface104 can be disposed on thewiring substrate102, which can provideelectrical connections106 between theinterface104 andelectrical terminals108, which can be disposed on alower surface110 of thewiring substrate102. Thewiring substrate102 can be, for example, a wiring board such as a printed circuit board, a ceramic substrate comprising internal and/or external electrical connections, or the like. Theelectrical connections106 can be, for example, electrically conductive vias and/or traces on and/or in thewiring substrate102. Thelower surface110 of thewiring substrate102 can be, for example, substantially parallel with the x, y plane
• As illustrated inFIGS. 1A and 1B, theprobe assembly120 can comprise electricallyconductive probes140 disposed in guide holes126 and130 in upper andlower guide plates124 and128, which can be disposed in aframe122. As shown, theupper guide plate124 and thelower guide plate128 can be attached to or disposed in theframe122 such that theguide plates124 and128 are substantially parallel and spaced apart. For example, theguide plates124 and128 can be substantially parallel to thesurface110 of thewiring substrate102, which as discussed above can be substantially parallel with the x, y plane. As also shown, there can be upper guide holes126 in theupper guide plate124 and corresponding lower guide holes130 in thelower guide plate128, and theprobes140 can be disposed in the guide holes126 and130. As can be seen inFIG. 1C, sidewalls160 of each of theupper holes126 can be substantially parallel with the z axis.
• As shown inFIG. 1B, eachprobe140 can comprise abase end142, acontact end150, and an elongatedflexible body146 between thebase end142 and thecontact end150. As shown, thebase end142 and thecontact end150 can be at opposite ends of theprobe140. As can be seen inFIG. 1B, anupper portion144 of thebody146 of eachprobe140 can be disposed inside one of the upper guide holes126 of theupper guide plate124, and alower portion148 of eachprobe140 can be disposed in a corresponding one of the lower guide holes130 in thelower guide plate128. As shown, theupper portion144 can be a part of thebody146 that is adjacent thebase end142, and thelower portion148 can be a part of thebody146 that is adjacent thecontact end150. The width, thickness, diameter, or like dimension of thebody146 of eachprobe140 can be smaller than the width, thickness, diameter, or like dimension of the corresponding upper andlower holes126 and130 so that theprobe140 can move (e.g., slide) substantially in the z direction in theholes126 and130. Theprobes140 can thus be said to “float” in theguide plates124 and128. As used herein, “float” or “floating” thus means that theprobes140 can move (e.g., slide) substantially in the z direction in theholes126 and130 in theguide plates124 and128.
• As shown inFIG. 1B, theframe122 can be coupled to thewiring substrate102 such that the base ends142 of theprobes140 are in contact with or at least in proximity to theterminals108 of thewiring substrate102. As also shown,terminals182 of anelectronic device180 can be moved M into contact with and pressed against the contact ends150 of theprobes140. The resulting contact forces substantially in the z direction on the contact ends150 of theprobes140 can push the base ends142 of theprobes140 firmly against theterminals108 of thewiring substrate102 and then bend or even buckle theelongated bodies146 of theprobes140. This can create pressure based electrical connections between theprobes140 and theterminals182 of theelectronic device180 and thus establish electrical connections from theterminals182 through theprobes140 andelectrical connections106 to theinterface104.
• Because theprobes140 float in theguide plates124 and128 as discussed above, it is possible that one or more of theprobes140 could move (e.g., shift, slide, or the like) in an undesirable manner in theirguide holes126 and130 or even fall out of the guide holes126 and130 in response to forces other than contact with theelectronic device180. For example, the force of gravity, the force from cleaning media (e.g. gel-based cleaning media), the force from adhesion of theprobe tip150 to theterminals182, the force of an incidental jarring of theprobe card assembly100, or the like could cause such an unwanted movement in one or more of theprobes140 in the guide holes126 and130 or one or more of theprobes140 could even fall out of the guide holes126 and130.FIG. 1C illustrates features of eachprobe140 that can prevent such unwanted movement of theprobes140.
• As shown inFIG. 1C, thebase end142 of eachprobe140 can be larger than the correspondingupper guide hole126, which can prevent theprobe140 from falling out of theguide hole126. Theoversized base end142 can thus function as a stop.
• As also shown inFIG. 1C, theupper portion144 of thebody146 of eachprobe140 can comprise a spring mechanism162 (which can be an example of a first spring mechanism), which can comprise one or more spring structures that exert normal forces against thesidewalls160 of the correspondingupper guide hole126. This can result in a frictional force between thespring mechanism162 and thesidewalls160 that is substantially parallel to thesidewalls160. Thespring mechanism162 can be sized and configured to provide a frictional force against thesidewalls160 that is sufficiently strong to hold theprobe140 in place in theupper guide hole126 against the force of gravity on theprobe140, the force of an incidental jarring or bumping of theprobe card assembly100, or a similar unintended force on theprobe140. The frictional force, however, can be significantly less than the force of contact between thecontact end150 of aprobe140 and aterminal182 of theelectronic device180 as the terminal182 is pressed against thecontact end150 as discussed above. The size and configuration of thespring mechanism162 can also be such that the frictional force against thesidewalls160 is sufficiently weak to allow theprobe140 to move in a z direction in the correspondingupper guide hole126 in response to the force of contact with theelectronic device180 as discussed above. For example, the contact force can be greater than the frictional force created by thespring mechanism162, which can be greater than the force of gravity on theprobe140. For example, the contact force of a terminal182 on thecontact end150 of a probe140 (e.g., sufficient to bend or even buckle theelongated body146 of the probe140) can be two or more times the frictional force, which can be two or more times the force of gravity on theprobe140.
• Theprobe card assembly100 illustrated inFIGS. 1A-1C is an example only, and variations are contemplated. For example, theprobe card assembly100 can include additional substrates, electrical connectors, and/or wiring boards (not shown) disposed, for example, between theframe122 and thewiring substrate102. Theterminals108 can be on any such substrate, electrical connector, or wiring board (not shown) rather than on thelower surface110 of thewiring substrate102. As another example, thespring mechanism162 can alternatively be part of thelower portion148 of thebody146 of eachprobe140 disposed in alower hole130 in thelower guide plate128.
• Thespring mechanism162 illustrated inFIG. 1C can comprise any kind of spring structure or spring structures. For example, in some embodiments, thespring mechanism162 can comprise one or more compressible flexures.FIGS. 2A-2C illustrate an example of a compressible flexure in the form of acantilevered beam204 and aspace206 between thecantilevered beam204 and amain part202 of theupper portion144 of thebody146 of theprobe144.
• As illustrated inFIG. 2A (which shows a side, cross-sectional view of part of the probe140), theupper portion144 of thebody146 of theprobe140 can comprise acantilevered beam204 that is spaced from amain part202 of theupper portion144 of thebody146. As shown, the cantileveredbeam204 can be elongated from abase end230, which can be coupled to (e.g., attached to or integrally formed with) themain part202 of theupper portion144 of thebody146, to afree end228. Alternatively, the “free”end228 is not free but is attached to themain part202 of the upper portion of thebody146 as shown in the example ofFIG. 3, which is discussed below. Regardless, with reference toFIG. 2A, there can bespace206 between thecantilevered beam204 and themain part202, which can allow the cantileveredbeam204 to move toward themain part202. For example, the cantileveredbeam204 can rotate about thebase230 until thefree end228 contacts themain part202 as illustrated inFIG. 2B.
• Thecantilevered beam204 can comprise material with spring (i.e., resilient) properties and can be formed such that, as thecantilevered beam204 rotates such that thefree end228 moves toward themain part202, the cantileveredbeam204 is in an at least partially compressed state and provides a spring force F that tends to restore the cantileveredbeam204 to the uncompressed state in which the cantileveredbeam204 is separated from themain part202 by the original size of thespace206 as shown inFIG. 2A. Thecantilevered beam204 is thus an example of a spring element.
• As shown inFIG. 2A, in an uncompressed state, the elongated length of the cantileveredbeam204 can be disposed along an axis222 (hereinafter referred to as the beam axis222), which can be oriented at anangle224 with respect to anaxis220 that is substantially parallel to the z axis. As noted above, the z axis can be substantially parallel to thesidewalls160 of anupper hole126 in theupper guide plate126. Theangle224 can be, for example, substantially zero or can be greater than zero degrees. For example, theangle224 can be at least two, three, four, five, ten, fifteen, twenty, or twenty five degrees. As shown inFIG. 2B, in a fully compressed state (i.e., thefree end228 is moved against themain part202 as shown inFIG. 2B), theangle224′ between theaxis220 and thebeam axis222′ can be less than theangle224 in the uncompressed state shown inFIG. 2A.FIG. 2C illustrates the cantileveredbeam204 in a partially compressed state in which theangle224″ between theaxis220 and thebeam axis222″ is less than theangle224 in the uncompressed state shown inFIG. 2A but greater than theangle224′ in the fully compressed state shown inFIG. 2B. It is noted that, in the partially compressed state of the cantileveredbeam204 shown inFIG. 2C, thespace206 between thefree end228 of the cantileveredbeam204 and themain part202 can be less than thespace206 between thefree end228 of the cantileveredbeam204 and themain part202 in the uncompressed state shown inFIG. 2A.
• As shown inFIG. 2A, while the cantileveredbeam204 is in the uncompressed state, the lateral (normal to the z axis) width Wu of thefree end228 of the cantileveredbeam204, thespace206, and themain part202 normal to theaxis220 can be greater than the lateral width Wh of theguide hole126. As noted, theaxis220 can be substantially parallel to the sidewalls160 (which can be oriented substantially parallel to the z axis) of theguide hole126. As illustrated inFIG. 2B, while the cantileveredbeam204 is in a fully compressed state, the lateral width Wfc of thefree end228 of the cantileveredbeam204, thespace206, and themain part202 normal to theaxis220 can be less than the width Wh of theguide hole126. As illustrated inFIG. 2C, while the cantileveredbeam204 is in a partially compressed state, the lateral width Wpc of thefree end228 of the cantileveredbeam204, thespace206, and themain part202 normal to theaxis220 can be equal to the width Wh of theguide hole126. As shown inFIGS. 2A and 2B, the lateral uncompressed width Wu and the lateral fully compressed width Wfc can be greater than the lateral width Wb of thebody146 of theprobe140, and the lateral width Wb can be less than the lateral width Wh of the hole.
• As illustrated in the transition fromFIG. 2A toFIG. 2C, starting from the contact end150 (seeFIG. 1B), theprobe140 can be inserted into theguide hole126. As shown inFIG. 2C, because the uncompressed lateral width Wu illustrated inFIG. 2A is greater than the lateral width Wh of theguide hole126, the cantileveredbeam204 can compress at least partially inside theguide hole126 and thus exertnormal forces226 against thesidewalls160 of theguide hole126. The normal forces266 of the cantileveredbeam204 against thesidewalls160 can create a frictional force F_fbetween thecantilevered beam204 and thesidewalls160. This frictional force F_fcan act in directions that are substantially parallel to the z axis and thus prevent unwanted motion or float of theprobe140 in the z direction. Thecantilevered beam204 andspace206 can be sized and configured such that the foregoing frictional force F_fis substantially less than the force of contact of aterminal182 of theelectronic device180 as the terminal182 is pressed against thecontact end150 of theprobe140 as discussed above, and such that the frictional force F_fis substantially greater than the force of gravity F_gon theprobe140. Thus, the cantileveredbeam204 andspace206 can be sized and configured such that the contact force of the terminal182 being pressed against thecontact end150 of a probe140 (e.g., sufficient to bend or even buckle thebody146 of the probe140) is greater than (e.g., 1.5, 2, 3, 4, 5, or more times) the frictional force F_f, and the frictional force F_fis greater than (e.g., 1.5, 2, 3, 4, 5, or more times) the force of gravity F_gon theprobe140.
• Configured with the cantileveredbeam204 ofFIGS. 2A-2C as thespring mechanism162 inFIGS. 1A-1C, the cantileveredbeam204 of each of theprobes140 in theprobe card assembly100 ofFIGS. 1A-1C can thus inhibit unwanted movement of theprobes140 within theguide plates124 and128 while allowing, in some embodiments, movement in response to larger forces from contact with an electronic device and allowing for sufficiently high contact forces between theterminals182 of theelectronic device180 and the contact ends150 of theprobes140 to establish low resistance electrical connections between theprobes140 and theterminals182
• Thecantilevered beam204 separated by aspace206 from amain part202 of theupper portion144 of theprobe body146 is but an example of thespring mechanism162.FIGS. 3 and 4 illustrate additional examples.
• As shown inFIG. 3 (which shows a side, cross-sectional view of part of the probe140), theupper portion144 of thebody146 of theprobe140 can comprise multipleelongated beams302 and312 separated from each other by aspace308, which can allow thebeams302 and312 to move toward each other. As shown, eachbeam302 and312 can be coupled at its ends to thebody146 of theprobe140. For example, thebeam302 can be coupled at afirst end304 and a secondopposite end306 to thebody146, and thebeam312 can be coupled at afirst end314 and a secondopposite end316 to thebody146.
• Like the cantileveredbeam204, thebeams302 and312 can comprise material with spring (i.e., resilient) properties and can be formed such that, as thebeams302 and312 are pressed through thespace308 toward each other, thebeams302 and312 are in an at least partially compressed state and provide a spring force that tends to restore thebeams302 and312 to the uncompressed state in which thebeams302 and312 are separated from each other by the original size of thespace308. Thebeams302 and312 are thus examples of spring elements, and thebeams302 and312 andspace308 are an example of a compressible flexure that can be an example of thespring mechanism162 ofFIGS. 1A-1C.
• As illustrated inFIG. 4 (which shows a side, cross-sectional view of part of the probe140), theupper portion144 of thebody146 of theprobe140 can comprise abeam402 that, like the cantileveredbeam204 discussed above, is spaced from amain part202 of theupper portion144 of thebody146. Also like the cantileveredbeam204 ofFIGS. 2A-2C, thebeam402 can be elongated from afirst end406 to a secondopposite end404. Unlike the cantileveredbeam204, however, thebeam402 is coupled at both ends404 and406 to themain part202 of theupper portion144 of thebody146. As shown, there can bespace408 between thebeam402 and themain part202, which can allow thebeam402 to move toward themain part202.
• Like the cantileveredbeam204, thebeam402 can comprise material with spring (i.e., resilient) properties and can be formed such that, as thebeam402 is pressed through thespace408 toward themain part202, thebeam402 is in an at least partially compressed state and provides a spring force that tends to restore thebeam402 to the uncompressed state in which thebeam402 is separated from themain part202 by the original size of thespace408. Thebeam402 is thus an example of a spring element, and thebeam402 andspace408 are an example of a compressible flexure that can be an example of thespring mechanism162 ofFIGS. 1A-1C.
• As discussed above, the base end142 (seeFIG. 1C) of aprobe140 can be larger than a correspondingupper guide hole126, which can prevent theprobe140 from falling out of theguide plates124 and128. This can, however, also prevent aprobe140 from being intentionally removed from theguide plates124 and128 unless theprobe card assembly100 is first dissembled.
• FIGS. 5A-5C illustrate theprobe card assembly100 in which thebase end542 of theprobe140 comprises a compressible stop structure. It is noted that any of theprobes140 illustrated in the Figures can be configured with thebase end542 shown inFIGS. 5A-5C rather than thebase end142.
• As shown inFIG. 5B, in an uncompressed state, thebase end542 is larger than theupper guide hole126. As shown inFIG. 5C, application of a sufficiently large downward (parallel to thesidewalls160 of the upper guide hole126) pulling force F_pto theprobe body146 can pull thebase end542 into theguide hole126, compressing thebase end542 to the size of theguide hole126. The pulling force F_pcan alternatively be another type force such as a pushing force. This can allow aprobe140 to be pulled out of theguide hole126 and acorresponding guide hole130 in thelower guide plate128 upon application of a sufficiently large pulling force F_p. Absent the pulling force F_p, however, thebase end542 functions as a stop the same as thebase end142 as discussed above. For example, thebase end542 can prevent theprobe140 from falling out of theguide plates124 and128.
• Thebase end542 can be structured so that the force F_prequired to pull thebase end542 into and then out of theupper guide hole126 is greater than the force of gravity F_gon theprobe140 and even greater than the contact force (e.g., a force of contact that bends or even buckles theelongated body146 of a probe140) on theprobe140 as aterminal182 of theelectronic device180 is pressed against thecontact end150 of theprobe140 as discussed above. For example, the force pulling F_pcan be 3, 4, 5, or more times the force of gravity F_gon theprobe140, and the pulling force F_pcan be 1.5, 2, 3, or more times the aforementioned contact force.
• Aprobe140 with thecompressible base end542 shown inFIGS. 5A-5C can be pulled out of theguide plates124 and128 and thus removed from theprobe card assembly100 while theprobe card assembly100 is fully assembled. It is also noted that aprobe140 not initially part of theprobe card assembly100 can be added to theprobe card assembly100 while theprobe card assembly100 is fully assembled by pushing thebase end542 through the lower and upper guide holes130 and126 with the opposite of the pulling force F_p, which is thus the reverse of the pulling action for removing aprobe140 discussed above. The foregoing can allow, for example, a damagedprobe140 to be removed from theprobe card assembly100 and replaced with anew probe140 without dissembling theprobe card assembly100 or even the probe assembly120 (seeFIGS. 1A-1C).
• Thecompressible base end542 can illustrated inFIGS. 5A-5C can comprise any kind of spring structure or spring structures. For example, in some embodiments, thebase end542 can comprise one or more compressible flexures.FIGS. 6A and 6B illustrate one example, andFIGS. 7A and 7B illustrate another example.
• As shown inFIG. 6A, thebase end542 can comprise a compressible flexure in the form of acantilevered beam604 and aspace608 between thecantilevered beam604 and amain part602 of thebase end542. In such a configuration, thebase end542 is in some ways similar to the configuration of thespring mechanism162 illustrated inFIGS. 2A-2C.
• As shownFIG. 6A, the cantileveredbeam604 can be elongated from afirst end630, which can be coupled to (e.g., attached to or integrally formed with) themain part602, to afree end628. Moreover, there can bespace608 between thecantilevered beam604 and themain part602, which can allow the cantileveredbeam604 to move toward themain part602. For example, the cantileveredbeam604 can rotate about thefirst end630 until thefree end628 contacts themain part602.
• Thecantilevered beam604 can comprise material with spring (i.e., resilient) properties and can be formed such that, as thecantilevered beam604 rotates such that thefree end628 moves toward themain part602, the cantileveredbeam604 is in an at least partially compressed state and provides a spring force that tends to restore the cantileveredbeam604 to the uncompressed state in which the cantileveredbeam604 is separated from themain part602 by the original size of thespace608.
• As shown inFIG. 6A, in an uncompressed state, the lateral width Wb of the cantileveredbeam604, thespace608, and themain part602 is wider than the width Wh (seeFIG. 6B) of theguide hole126. Uncompressed, the cantileveredbeam604 thus functions as a stop that prevents thebase end542 from moving into theguide hole126. As shown inFIG. 6B, application of the pulling force F_pto theprobe body146 compresses the cantileveredbeam604 at least partially, allowing thebase end542 to be pulled into theguide hole126 as shown and ultimately out of theguide hole126 as discussed above.
• FIGS. 7A and 7B illustrate an alternative configuration in which thebase end542 comprises abulb structure704 with ahollow interior708. As illustrated inFIG. 7A, while thebulb structure704 is in an uncompressed state, the lateral width Wb of thebulb structure704 is wider than the width Wh (seeFIG. 7B) of theguide hole126. Uncompressed, thebulb structure704 thus functions as a stop that prevents thebase end542 from moving into theguide hole126. As shown inFIG. 7B, application of the pulling force Fp to theprobe body146 compresses thebulb structure704 into the hollowinterior space708, allowing thebase end542 to be pulled into theguide hole126 as shown and ultimately out of theguide hole126 as discussed above.
• Although theprobe140 is illustrated inFIGS. 6A-7B with the cantileveredbeam204 ofFIGS. 2A-2C, theprobe140 can alternatively have other configurations of thespring mechanism162 such as thebeams302 and312 shown inFIG. 3 and thebeam402 shown inFIG. 4.
• Embodiments of the invention illustrated and discussed herein can provide advantages. One such advantage is illustrated inFIG. 8.
• FIG. 8 illustrates atest system800 in which theprobe card assembly100 can be used to test anelectronic device180 comprising input and/oroutput terminals182. As shown, theinterface104 can be connected throughcommunications channels804 to atester802, which can comprise test equipment (e.g., a programmed computer) for providing power, control signals, and/or test signals through thecommunications channels804 andprobe card assembly100 toterminals182 of theelectronic device180. Thetester802 can also monitor through theprobe card assembly100 andcommunications channels804 response signals generated by theelectronic device180. Thetester802 can thus control testing of theelectronic device100.
• Prior to testing, theelectronic device180 can be disposed on amoveable support810.Cameras812 can capture images of the contact ends150 of theprobes140 and theterminals182 of theelectronic device180, and acontroller814 can move in the x, y plane thesupport810 so that theterminals182 align with correspond contact ends150 of theprobes140. Once theterminals182 are aligned with corresponding contact ends150, thecontroller814 can cause thesupport810 to move theelectronic device180 in the z direction so that theterminals182 contact and are pressed against the corresponding contact ends150 of theprobes140, establishing pressured based electrical connections between theterminals182 and theprobes140 and thus complete electrical paths between thetester802 and theterminals182 of theelectronic device180.
• If any of theprobes140 fall out of the probe card assembly100 (e.g., by falling out of theguide plates124 and128 due to the force of gravity or a jarring or bumping of theprobe card assembly100 as discussed above), there will not be an electrical connection from thetester802 tocorresponding terminals182 of theelectronic device180. Moreover, even if any of theprobes140 merely move inadvertently in the z direction, the contact ends150 of thoseprobes140 can be difficult to detect in the images from thecameras812, and it can be difficult to align theterminals182 with the contact ends182. Because thespring mechanisms162, whether configured as thecantilevered beam204 ofFIGS. 2A-2C or otherwise, can impede inadvertent movement of theprobes140 in theholes126 of theguide plate124, thespring mechanism162 can overcome the foregoing problems and/or other problems.
• FIGS. 9 and 10 illustrate examples of alternative ways of inducing normal forces of a probe against sidewalls of a guide hole. As will be seen, the examples shown inFIGS. 9 and 10 utilize thebody146 of theprobe140 as a spring mechanism that induces the normal forces.
• In the example shown inFIG. 9, theupper guide hole126 in theupper guide plate124 is substantially aligned with thelower guide hole130 in thelower guide plate128 along anaxis902 that is substantially parallel with thesidewalls160 of theguide hole126. Thelower portion148 of theprobe body146, however, can be offset from theupper portion144 of thebody146. (As discussed above, thelower portion148 is disposed inside aguide hole130 in thelower guide plate128, and theupper portion144 is disposed inside aguide hole126 in theupper guide plate124.) For example, as shown inFIG. 9, thelower portion148 can be spaced an offsetdistance904 from theupper portion144. The offsetdistance904 can be substantially perpendicular to thesidewalls160 of theguide hole126.
• Due to the offsetdistance904, theguide plates124 and128 can preload theprobe140 such that thebody146 of theprobe140 functions as a spring and causes theupper portion144 of theprobe body146 to exertnormal forces906 against thesidewalls160 of theguide hole126 as shown inFIG. 9. As discussed above, thesidewalls160 of theguide hole126 are oriented in the z direction, and thenormal forces906, which are normal to thesidewalls160, are thus substantially perpendicular to thesidewalls160.
• Thenormal forces906 can have any of the characteristics of thenormal forces226 discussed above. For example, theprobe140 and offsetdistance904 can be configured and sized such that thenormal forces906 create frictional forces that are parallel to thesidewalls160 and impede unwanted movement in the z direction of theprobe140. In some embodiments, thenormal forces906, and thus the resulting frictional forces, can be 2, 3, 4, 5, or more times the force of gravity F_gon theprobe140.
• As shown inFIG. 10, a similar result can be obtained by offsetting theguide hole126 in theupper guide plate124 from theguide hole130 in thelower guide plate128. That is, in the example illustrated inFIG. 10, thelower portion148 of theprobe body146 can be aligned with theupper portion144 along anaxis1002 that is substantially parallel to thesidewalls160, but theguide hole130 in thelower guide plate128 can be offset from theguide hole126 in theupper guide plate124. For example, as shown inFIG. 10, theguide hole130 can be spaced an offsetdistance1004 from theguide hole126. The offsetdistance1004 can be substantially perpendicular to thesidewalls160 of theguide hole126. This can be accomplished, for example, by aligning the guide holes126 and130 during assembly and then, after theprobe140 is inserted into the guide holes126 and130, shifting theguide plates124 and128 relative to each other by the offsetdistance1004.
• Due to the offsetdistance1004, theguide plates124 and128 can preload theprobe140 such that thebody146 of theprobe140 functions as a spring and causes theupper portion144 of theprobe body146 to exertnormal forces1006 against thesidewalls160 of theguide hole126 as shown inFIG. 10. As discussed above, thesidewalls160 of theguide hole126 are oriented in the z direction, and thenormal forces1006, which are normal to thesidewalls160, are thus substantially perpendicular to thesidewalls160.
• Thenormal forces1006 can have any of the characteristics of thenormal forces226 discussed above. For example, theprobe140 and offsetdistance1004 can be configured and sized such that thenormal forces1006 create frictional forces that are parallel to thesidewalls160 and impede unwanted movement in the z direction of theprobe140. In some embodiments, thenormal forces1006, and thus the resulting frictional forces, can be 2, 3, 4, 5, or more times the force of gravity F_gon theprobe140.
• Although specific embodiments and applications of the invention have been described in this specification, these embodiments and applications are exemplary only, and many variations are possible.

Claims (22)

We claim:

1. A probe card assembly comprising:

electrically conductive terminals disposed on a substrate; and

a probe assembly coupled to said substrate, said probe assembly comprising:

a guide plate comprising guide holes; and

electrically conductive probes, each said probe comprising a base end, a contact end, and an elongated flexible body between said base end and said contact end, wherein a portion of said body of said probe is disposed inside one of said guide holes and comprises a spring mechanism configured to exert a normal force against sidewalls of said one of said guide holes sufficiently to reduce movement of said probe in said one of said guide holes.

2. The probe card assembly ofclaim 1, wherein said spring mechanism comprises a compressible flexure structure.

3. The probe card assembly ofclaim 2 further comprising an interface to a tester for testing an electronic device, wherein said probes are electrically connected to said terminals, which are electrically connected to said interface.

4. The probe card assembly ofclaim 2, wherein said normal force against said sidewalls of said one of said guide holes results in a frictional force that is substantially parallel to said sidewalls.

5. The probe card assembly ofclaim 4, wherein said frictional force is at least two times greater than a force of gravity on said probe.

6. The probe card assembly ofclaim 5, wherein a contact force on said contact end of said probe sufficient to bend or buckle said elongated body of said probe is at least two times said frictional force.

7. The probe card assembly ofclaim 5, wherein a contact force on said contact end of said probe from contact with a terminal of an electronic device that is sufficient to establish an electrical connection between said probe and said terminal is at least two times said frictional force.

8. The probe card assembly ofclaim 2, wherein in an uncompressed state, a lateral width of said compressible flexure structure is greater than a lateral width of said one of said guide holes.

9. The probe card assembly ofclaim 9, wherein disposed in said one of said guide holes, said compressible flexure structure is at least partially compressed.

10. The probe card assembly ofclaim 2, wherein said compressible flexure structure comprises a moveable spring element.

11. The probe card assembly ofclaim 10, wherein said moveable spring element comprises a cantilevered beam that extends from a main part of said portion of said body disposed inside said one of said guide holes.

12. The probe card assembly ofclaim 11, wherein:

said cantilevered beam comprises a base coupled to said main part of said portion of said body and a free end opposite said base,

said cantilevered beam is elongated from said base to said free end, and

said free end of said cantilevered beam is moveable through a space between said free end and said main part of said portion of said body.

13. The probe card assembly ofclaim 12, while said cantilevered beam is in an uncompressed state, a lateral width of said free end, said space, and said main part of said portion of said body is wider than a lateral width of said one of said guide holes.

14. The probe card assembly ofclaim 13, wherein disposed in said one of said guide holes, said cantilevered beam is in an at least partially compressed state in which said space between said free end and said main part of said portion is smaller than said space when said cantilevered beam is in said uncompressed state.

15. The probe card assembly ofclaim 12, wherein an angle between a beam axis through said base and said free end of said cantilevered beam and an axis parallel to said sidewalls of said one of said guide holes is at least one degree.

16. The probe card assembly ofclaim 10, wherein said moveable spring element comprises a beam comprising:

a first end coupled to a main part of said portion of said body disposed inside said one of said guide holes,

a second end opposite said first end and coupled to said main part of said portion of said body, and

an elongated body between said first end and said second end,

wherein there is a space between said elongated body of said beam and said main part of said portion of said body.

17. The probe card assembly ofclaim 2, wherein said base end of said probe is disposed outside of said one of said guide holes and comprises a compressible flexure.

18. The probe card assembly ofclaim 17, wherein:

while said compressible flexure is in an uncompressed state, said compressible flexure is wider than said one of said guide holes and prevents said base from moving into said guide hole, and

application of a sufficiently large force to said body of said probe compresses and moves said compressible flexure into said guide hole.

19. The probe card assembly ofclaim 18, wherein said force is at least two times greater than a force of gravity on said probe.

20. The probe card assembly ofclaim 1, wherein said base end of said probe is disposed outside of said one of said guide holes and is wider than said one of said guide holes and prevents said base from moving into said guide hole.

21. The probe card assembly ofclaim 1, wherein:

said guide plate is an upper guide plate,

said one of said guide holes is an upper guide hole in said upper guide plate,

said portion of said probe disposed inside said one of said guide holes is an upper portion of said body of said probe adjacent said base end,

said probe card assembly further comprises a lower guide plate comprising lower guide holes,

said probe further comprises a lower portion of said body disposed in inside one of said lower guide holes,

said one of said guide holes is substantially aligned with said one of said lower guide holes along an axis that is substantially parallel to said sidewalls, and

said upper portion of said probe is sufficiently offset from said lower portion of said probe in a direction that is substantially perpendicular to said sidewalls that said upper portion of said probes presses against said sidewalls with said normal force.

22. The probe card assembly ofclaim 1, wherein:

said guide plate is an upper guide plate,

said one of said guide holes is an upper guide hole in said upper guide plate,

said portion of said probe disposed inside said one of said guide holes is an upper portion of said body of said probe adjacent said base end,

said probe card assembly further comprises a lower guide plate comprising lower guide holes,

said probe further comprises a lower portion of said body disposed in inside one of said lower guide holes,

said upper portion of said probe is substantially aligned with said lower portion of said probe along an axis that is substantially parallel to said sidewalls, and

said one of said guide holes is sufficiently offset from said one of said lower guide holes in a direction that is substantially perpendicular to said sidewalls that said upper portion of said probe presses against said sidewalls with said normal force.

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